Antithrombocyte antibodies in the serum and on the surface of the thrombocytes in patients with chronic lymphoproliferative diseases

: Antiplatelet antibodies were studied in patients with chronic lymphatic leukemia (CLL) using ELISA for detection of serum antibodies and RIA for determination of antibodies associated with platelet surface. Serum antibodies were identified in 1 out of 6 CLL patients with the platelet count 100,000-200,000 per microliter and in 7 out of 54 CLL patients with the platelet count lower than 100,000. Platelet-associated antibodies were not detected in patients with the normal platelet count, but were revealed in 14 out of 25 patients with the platelet count 100,000-200,000 per microliter and in 21 of 27 patients with the platelet count lower than 100,000 per microliter. The presence of a group of thrombocytopenic patients lacking serum or platelet-associated antibodies suggested that the development of thrombocytopenia in CLL could be mediated not only by antibodies but also by other pathogenic mechanisms, i.e. by the depression of megakaryocytes in bone marrow. Increase of the platelet count after steroid and cytostatic treatment in CLL patients correlated with decrease of antiplatelet antibodies. In splenectomized CLL patients, the increase of the platelet count and disappearance of hemorrhage occurred in patients with the low level as well as with the high level of antibodies after the operation.